Field of the Invention
The present invention relates to a drip-proof structure around connectors for unit connection of an electronic apparatus, in which a modularized unit configured so that a printed circuit board mounted with an electronic component and a connector is housed in a housing and a unit configured so that a printed circuit board mounted with an electronic component and a connector is secured to a housing are connected by the connectors for operation.
Description of the Related Art
A control panel of a machine tool will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, a numerical controller 1 is mounted on a housing of a control panel 2. An electronic apparatus such as an I/O unit 4 is mounted on an inner wall 13 of the control panel 2, as shown in FIG. 2, and is used in a severe factory environment in which a cutting fluid is used.
For such an electronic apparatus as the I/O unit 4, a user selects a plurality of modules 5 with different functions as required. During use, therefore, the electronic apparatus is unitized including a base unit 6 secured to the control panel 2 and the modules 5 removably connected to the base unit 6 by connectors (see Japanese Patent Application Laid-Open No. 1-232800).
In order to protect the interior of the control panel 2 from the factory environment, gaskets are disposed between the control panel 2 and an electronic apparatus such as the numerical controller 1 and in a cable inlet hole 3 opening into the control panel 2. Thus, outside air, cutting fluid, etc., are prevented from getting into the control panel 2.
If the gaskets are degraded by aging or a harsh environment in which a large amount of cutting fluid continues to be supplied, however, the cutting fluid may sometimes get into the control panel 2. In such a case, as shown in FIG. 3, the cutting fluid flows along the inner wall of the control panel 2 (see fluid flow 23).
As shown in FIGS. 4 and 5, a housing 7 for the modules 5 is formed with a module-side opening 14 to which a module-side connector 11 can be attached, and a housing 8 for the base unit 6 is formed with a base-unit-side opening 16 to which a base-unit-side connector 12 can be attached. Thus, a liquid, such as the cutting fluid, flows through the housing 7 for the modules 5 and the housing 8 for the base unit 6 of the I/O unit 4 and reaches the module-side connector 11 and the base-unit-side connector 12, which electrically connect the units, thereby causing problems, such as contact failure of the connectors 11 and 12.